122 OF THE ARTERIES GENERALLY. 



existence is known with certainty, because their effects are 

 perceived. Thus the hardest part of bone is removed by a 

 natural process, or absorbed. Inorganized cartilage is like- 

 wise taken away ; to allow the arteries and veins to enter, 

 and bone to be deposited when ossification ensues. 



Absorbents are very minute, thin-coated, transparent 

 vessels, having numerous valves, like to veins ; they are 

 spoken of as deep-seated and superficial ; but as the differ- 

 ence of position is accompanied by no difference of struc- 

 ture, we shall here regard them as of one kind. Every 

 absorbent conveys the materials it takes away from various 

 parts into the blood ; with which their contents mingle, and 

 ultimately become blood ; or they are emitted with the excre- 

 tions. In starvation it is by means of the absorbents that 

 the marrow is carried out of bones ; and the fatty matter 

 from other places in the body, and emptied into the blood ; 

 which in this manner helps to support, or keep alive, the 

 subject starved. It is thus that it is accounted for why a 

 fat animal is longer dying from starvation than one that 

 is thin. 



Certain absorbents, which take up the nutritive portion 

 from the food within the intestines, are called lacteals ; be- 

 cause the substance they abstract is at first white, like to 

 milk ; otherwise they are the same as common absorbents ; 

 all of which enter and pass through one or more of the 

 little reddish bodies, called absorbent glands. Of what use 

 these glands are remains to be discovered ; but they doubt- 

 less promote some change in the fluid contents of the ab- 

 sorbent vessels ; they also serve to mingle what the vessels 

 contain ; for if two or three absorbent branches enter a 

 gland, only one is seen to leave it ; which one must convey 

 away the materials the others brought ; as the glands them- 

 selves do not appropriate, or enlarge, or fatten, upon the 

 contents of these vessels. 



The functional effects of this system are abundantly active 

 in the constitution at large ; we are certain that the various 

 organs of the body are continually changing, wholly or 

 partially. It appears to be the office of the arteries to 

 build up new parts, and to repair the waste of others ; but 

 the old ones must be first of all pulled down and removed 



